Abstract

To investigate the growth and the thermoelectric properties of nitrogen-doped diamond, samples were grown by microwave plasma chemical vapor deposition with varying nitrogen flows as well as with a high nitrogen flow and varying methane flows. The samples were characterized according to their morphology, phase composition, electrical conductivity, and Seebeck coefficient. It was found that an increased nitrogen flow leads to a higher fraction of sp-bond carbon. Furthermore, a structure consisting of graphene nanowalls which exhibits many cavities is created. For nitrogen flows above 70 sccm, the electrical conductivity increases abruptly and significantly from less than 0.3s/m to more than 4.3s/m. A lower methane flow inverts this development. It was not possible to find a clear dependency of the Seebeck coefficient on the nitrogen flow. Seebeck coefficients were measured between -17μV/K at 23°C and -34μV/K at 110°C.